Discuss the below:
Q: Write the standard form of the equation of the circle and graph:
1. With r = 3 and tangent both axes in Q1.
2. With C (-1, -3) and passing through (-2, 0).
3. With points (2, 5) and (6, -1) as ends of a diameter.
4. With C (0, 0) and touching the line 3x + 4y = 10.